Drawing-scale.



No. 637,857. Patentad Nov. 28, I899. J. DITSON.

DRAWING SCALE.

plicatio filed June 13, 1899 UNITED STATES PATENT OFFICE.

JESSE DITSON, OF DENVER, COLORADO.

DRAWING-SCALE.

SPECIFICATION forming part of Letters Patent No. 637,857, dated November 28, 1899.

Application filed June 131 1899.

To all whom it may concern.-

Be it known that I, JESSE DITsON, a citizen of the United States of America, residing at Denver, in the county of Arapahoe and State of Colorado, have invented certain new and useful Improvements in Drawing-Scales; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

My invention relates to drawing instruments; and its object is to provide a new and improved drawing-scale designed for conveniently, accurately, and quickly drawing screw-threads of any desired pitch, for drawing section-lines and parallel lines of equal or unequal distances apart, for drawing spiral springs, and for other purposes.

The invention consists of novel features and parts and combinations of the same, as will be fully described hereinafter and then pointed out in the claim.

Apractical embodiment of my invention is represented in the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views.

Figure 1 is a plan view of one face of the improvement. Fig. 2 is an edge view of the improvement. Fig. 3 is a plan view of the other face of the improvement, and Fig. i is a plan View of the improvement as applied for drawing threads of fourteen pitch.

My improved drawing scale consists of preferably a fiat thin triangular-shaped piece of any suitable material A, such as wood, celluloid, rubber, or metal. It may be built up of two or more pieces or may be formed from an integral piece of any suitable material. The sides form, with the base, an isosceles triangle. Along the edges of the long side of the scale graduations are made, dividing the length of the scale into spaces B, representing the number of threads to the inch of each pitch of thread it is desired to place on the scale. These graduations are proportioned to the rise of the angles of the sides of the scale, as will be described more Serial No. 720,382. (No model.)

fully hereinafter, and are not the same dis= tance apart on the scale as the lines drawn on a drawing to represent a pitch of thread, but bear the following proportion: pitch of thread, pitch of scale, width of scale, and length of scale, and it will be seen that this proportion will be true if we take any length and width of scale. Furthermore, with this scale the spacing is not done by laying off distances on the work and then by separate operation drawing lines through such marks, as is now commonly practiced, but spacing is done along the bolt-for instance, by bringing the lines of the graduated side or scale to coincide with any adapted line in the work, such coincidences bringing the scale in position to serve as a ruler or straight-edge along which to draw the required lines. By the arrangement described the usual two operations now practiced for drawing parallel lines are reduced to one operation, at the same time securing a greater degree of accuracy over the former method, especially as the length of the scale is greater than the width.

It is expressly understood that one of the main advantages and features of my invention is bringing the graduations of the moving scale to coincide with any stationary or fixed line, either inside oroutside of the work, to determine the-spacing of the lines to be drawn. The wide or base end 0 of the triangles is provided with graduations O for indicating the depth of the screw-threads corresponding to the respective graduations B. These graduations G for depth of the standard or any other screw-threads may be made just as well along the side of its angles, and it is not absolutely necessary that the base of said angles be a right angle in a triangle, as a simple triangle may be used, or the taper ing sides of the angular scale may be joined by any are of a circle or other curve. The graduations are laid ofi according to the rise of the short side O or the taper of the triangle--that is, if the length of the scale has a one-inch taper or rise it is necessary to divide the length of each edge of the scale into a number of parts corresponding to the number of threads per inch of each thread represented on each edge--that is to say, if the taper is one inch to five inches then for fourteen threads per inch it is necessary that five inches on the scale must be divided into fourteen spaces, and for ten threads per inch into ten spaces, and so on.

In Figs. 1 and 2 I have illustrated a scale upon which a number of graduations have been laid off to illustrate my invention. My invention, however, is not limited to the number of different scales for threads I show or to the taper of the scale, as it can be made of any suitable taper, pitch, rise, or size, and it may be graduated to draw threads of any practicable pitch.

I In order to use the drawing-scale, say, on drawing-paper, as illustrated in Fig. 4, the diameter of the bolt, for instance, on which the threads are to be drawn at fourteen pitch is first laid off in the usual manner on the paper by the outside parallel lines D D, and the depth-lines D are then laid off from the graduation 0 corresponding to fourteen pitch. The lines D are then drawn parallel to the lines D D, and then the operator places the scale in such a position on the drawing-paper that the side containing the graduation for the fourteen pitch is uppermost at the upper edge of the body or stock A. 'With the help of a straight-edge E the upper edge of the body or stock A is now placed at a right angle to the lines D D, and the upper end line of the bolt is now drawn between the lines D D, as at D It is necessary before the pitchlines be drawn upon a drawing that some one of the lines D, D, orD be selected for a gage-line or that some new and independent line be drawn parallel to them and to the 1011- gitudinal axis of the bolt, and it is a feature of my invention that this gage-line may be located on the drawing wherever desired within the natural working movement of the scale. I preferably in Fig. 4 use a line D D, which I place at about the center of the bolt, although a line D D D, placed outside of the bolt, could just as well be used or the line D of the bolt. The scale is then placed so that its thick end will be close to the bolt, so as to have most of the length of the scale to draw the thread-lines without changing the position of the scale too often. Then one of the graduations of the fourteen threads to the inch is brought to register with the line D D. Then the scale is moved to the right on the straight-edge E, which is held stationary, a distance corresponding to half the distance of the fourteen-pitch graduation to obtain-the second position. (Indicatedin dotted lines in Fig. 4.) The operator now draws along the upper edge of the body A a point D on the line D, and then swings the body A to connect this point D with the point D at the intersection of the lines D D The line D D is now drawn. The straight-edge Eis moved in contact with the lower edge of the body A, and then the operator again slides the said body to the right half the distance between the fourteen-pitch or to the intermediate graduations between the main lines of the pitch and draws a second line parallel to the line D D from the line D to the other line D The body A is then again moved the same distance along the straight-edge E to draw still another parallel line to the previously-drawn line D D but from the line D to the line D. Thus alternate long and short lines are drawn between the lines D D and the lines D D and the outer ends of the adjacent lines are connected with each other by straight lines to indicate the side edges of the threads, as will be readily understood by reference to Fig. 4.

Having thus fully described my invention, I claim as new and desire to secure by Letters Patent In a drawing-scale, the combination of a quadrangular-shaped body, a plurality of graduations of different denominations upon the sides of said body adjacent to the side edges representing the pitch or number of threads per inch of different screw-threads, and a scale at the base of said triangle indicating the depth of the threads represented by the said pitch graduations, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

JESSE DITSON.

Witnesses:

JOHN GEORGE LYNER, JEssE EDWARD HOLMES. 

